Time Old Balancer with new chrome tab?
 

I had my 350 rebuilt and I kept the original harmonic balancer but bought a new chrome timing chain cover with a new timing tab. What I found out is the new balancers have moved the timing mark to somewhere around the 2 'o clock position where the old ones had them at around the 12 'o clock position.

What I am trying to do is find exactly how many degrees they moved this mark over (towards the drivers side) so I can draw a new line on the balancer, and time from it.

I got the motor running by ear, then set my timing gun to advance about 40 degrees and the old mark lined up at about 0 on the new timining tab, but I would like to get this as close as possible the 4 degrees BTDC (Specs from the Haynes Manual)

Any advice or suggestions would be appreciated,
Thanks

The best thing would be for you to set a new TDC mark. You can easily do it using a TDC tool that is inserted in place of the #1 spark plug and following instructions that come with the tool. About $10 to $15 in most part stores.

In a nutshell, you want to find an up stop position turning the engine clockwise by hand, and draw a line on the damper opposite the TDC line on the tab. And do the same thing turning the engine counter-clockwise. Between the two marks is true TDC.
Also, the timing recommendation in the manual is just that, a recommendation. Especially if the engine is non-stock. Use it as a starting point, then adjust your timing for as much advance you can get before the engine "pings" under a load (you'll hear it).

Thanks guys, I'll try the TDC tool and make my new line off of it.

The goal of this rebuild was to get the most horsepower/torque out of this motor. So when I took it to the motor shop they put their upgraded cams, etc. in it.

Now, what degree would you guys recommend timing the motor at to get the most performance out of it?